The present invention relates generally to medical methods, devices, and systems. In particular, the present invention relates to methods, devices, and systems for the endovascular or minimally invasive surgical repair of the atrioventricular valves of the heart, particularly the mitral valve.
Mitral valve regurgitation is characterized by retrograde flow from the left ventricle of a heart through an incompetent mitral valve into the left atrium. During a normal cycle of heart contraction (systole), the mitral valve acts as a check valve to prevent flow of oxygenated blood back into the left atrium. In this way, the oxygenated blood is pumped into the aorta through the aortic valve. Regurgitation of the valve can significantly decrease the pumping efficiency of the heart, placing the patient at risk of severe, progressive heart failure.
Mitral valve regurgitation can result from a number of different mechanical defects in the mitral valve. The valve leaflets, the valve chordae which connect the leaflets to the papillary muscles, or the papillary muscles themselves may be damaged or otherwise dysfunctional. Commonly, the valve annulus may be damaged, dilated, or weakened limiting the ability of the mitral valve to close adequately against the high pressures of the left ventricle. In some cases the mitral valve leaflets detach from the chordae tendinae, the structure that tethers them to the ventricular wall so that they are positioned to coapt or close against the other valve leaflet during systole. In this case, the leaflet “flails” or billows into the left atrium during systole instead of coapting or sealing against the neighboring leaflet allowing blood from the ventricle to surge into the left atrium during systole. In addition, mitral valve disease can include functional mitral valve disease which is usually characterized by the failure of the mitral valve leaflets to coapt due to an enlarged ventricle, or other impediment to the leaflets rising up far enough toward each other to close the gap or seal against each other during systole.
The most common treatments for mitral valve regurgitation rely on valve replacement or strengthening of the valve annulus by implanting a mechanical support ring or other structure. The latter is generally referred to as valve annuloplasty. A recent technique for mitral valve repair which relies on suturing adjacent segments of the opposed valve leaflets together is referred to as the “bow-tie” or “edge-to-edge” technique. While all these techniques can be very effective, they usually rely on open heart surgery where the patient's chest is opened, typically via a sternotomy, and the patient placed on cardiopulmonary bypass. The need to both open the chest and place the patient on bypass is traumatic and has associated morbidity.